retinol transport
Definition
Target type: biologicalprocess
The directed movement of retinol into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Retinol is vitamin A1, 2,6,6-trimethyl-1-(9'-hydroxy-3',7'-dimethylnona-1',3',5',7'-tetraenyl)cyclohex-1-ene, one of the three components that makes up vitamin A. [GOC:BHF, GOC:mah, GOC:vk]
Retinol, the alcohol form of vitamin A, is transported throughout the body in a complex and tightly regulated process. It begins with the absorption of dietary retinol from the small intestine, where it is incorporated into chylomicrons. These lipid-rich particles travel through the lymphatic system and enter the bloodstream, eventually reaching the liver. In the liver, retinol is esterified with fatty acids and stored in stellate cells.
When retinol is needed by tissues, it is released from the liver bound to retinol-binding protein (RBP). RBP is a small protein that specifically binds retinol and protects it from degradation. This complex, known as the retinol-RBP complex, travels in the bloodstream and binds to a larger protein called transthyretin (TTR). TTR provides stability to the complex and ensures its delivery to target tissues.
At target tissues, the retinol-RBP complex interacts with specific receptors on cell surfaces, known as STRA6. This interaction allows retinol to be internalized into the cell. Inside the cell, retinol is released from RBP and can be used for various metabolic processes, including the synthesis of retinal, a visual pigment, and retinoic acid, a hormone that plays a crucial role in cell growth and development.
The regulation of retinol transport is essential to maintain adequate levels of vitamin A in the body. The synthesis and secretion of RBP are tightly controlled, ensuring that the supply of retinol matches the demand of different tissues. Moreover, the levels of RBP in the bloodstream are regulated by the liver, which can adjust its production based on the body's needs.
Overall, the transport of retinol is a complex and sophisticated process involving multiple proteins and interactions. This process ensures that retinol, an essential nutrient, is efficiently delivered to tissues where it is needed to support various biological functions.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Retinol-binding protein 4 | A retinol-binding protein 4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P02753] | Homo sapiens (human) |
Compounds (5)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| retinol | all-trans-retinol : A retinol in which all four exocyclic double bonds have E- (trans-) geometry. retinol : A retinoid consisting of 3,7-dimethylnona-2,4,6,8-tetraen-1-ol substituted at position 9 by a 2,6,6-trimethylcyclohex-1-en-1-yl group (geometry of the four exocyclic double bonds is not specified). vitamin A : Any member of a group of fat-soluble retinoids produced via metabolism of provitamin A carotenoids that exhibit biological activity against vitamin A deficiency. Vitamin A is involved in immune function, vision, reproduction, and cellular communication. Vitamin A: Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of CAROTENOIDS found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products. | retinol; vitamin A | human metabolite; mouse metabolite; plant metabolite |
| fenretinide | 4-hydroxyphenyl retinamide : A retinoid obtained by formal condensation of the carboxy group of all-trans retinoic acid and the anilino group of 4-hydroxyaniline. Synthetic retinoid agonist. Antiproliferative, antioxidant and anticancer agent with a long half-life in vivo. Apoptotic effects appear to be mediated by a mechanism distinct from that of 'classical' retinoids. Fenretinide: A synthetic retinoid that is used orally as a chemopreventive against prostate cancer and in women at risk of developing contralateral breast cancer. It is also effective as an antineoplastic agent. | monocarboxylic acid amide; retinoid | antineoplastic agent; antioxidant |
| n-(2-hydroxyethyl)retinamide | N-(2-hydroxyethyl)retinamide: RN given refers to cpd without isomeric designation | ||
| tafamidis | tafamidis : A member of the class of 1,3-benzoxazoles that is 1,3-benzoxazole-6-carboxylic acid in which the hydrogen at position 2 is replaced by a 3,5-dichlorophenyl group. Used (as its meglumine salt) for the amelioration of transthyretin-related hereditary amyloidosis. tafamidis: may be effective in treating transthyretin amyloid polyneuropathy | 1,3-benzoxazoles; dichlorobenzene; monocarboxylic acid | central nervous system drug |
| idarucizumab |